Class: Switchman::DatabaseServer

Inherits:
Object
  • Object
show all
Defined in:
lib/switchman/database_server.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(settings = {}) ⇒ DatabaseServer

Returns a new instance of DatabaseServer.



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# File 'lib/switchman/database_server.rb', line 44

def initialize(settings = {})
  self.id = settings[:id]
  self.config = (settings[:config] || {}).symbolize_keys
end

Instance Attribute Details

#config ⇒ Object

Returns the value of attribute config.



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# File 'lib/switchman/database_server.rb', line 3

def config
  @config
end

#id ⇒ Object

Returns the value of attribute id.



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# File 'lib/switchman/database_server.rb', line 3

def id
  @id
end

Class Method Details

.all ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 6

def all
  database_servers.values
end

.create(settings = {}) ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 16

def create(settings = {})
  raise "database servers should be set up in database.yml" unless Rails.env.test?
  id = 1
  while database_servers[id.to_s]; id += 1; end
  server = DatabaseServer.new({ :id => id.to_s }.merge(settings))
  server.instance_variable_set(:@fake, true)
  raise "database server #{server.id} already exists" if database_servers[server.id]
  database_servers[server.id] = server
end

.find(id_or_all) ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 10

def find(id_or_all)
  return self.all if id_or_all == :all
  return id_or_all.map { |id| self.database_servers[id || Rails.env] }.compact.uniq if id_or_all.is_a?(Array)
  database_servers[id_or_all || Rails.env]
end

.server_for_new_shard ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 26

def server_for_new_shard
  servers = all.select { |s| s.config[:open] }
  return find(nil) if servers.empty?
  servers[rand(servers.length)]
end

Instance Method Details

#cache_store ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 169

def cache_store
  if !@cache_store
    @cache_store = Rails.cache_without_sharding if self.id == Rails.env
    # TODO: get the config from somewhere
    config = nil
    @cache_store ||= ActiveSupport::Cache.lookup_store(config) if config
    @cache_store ||= Rails.cache_without_sharding
    @cache_store.options[:namespace] = lambda { Shard.current.default? ? nil : "shard_#{Shard.current.id}" }
  end
  @cache_store
end

#create_new_shard(options = {}) ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 78

def create_new_shard(options = {})
  db_name = options[:db_name]
  create_schema = options[:schema]
  # look for another shard associated with this db
  other_shard = self.shards.where("name<>':memory:' OR name IS NULL").order(:id).first
  temp_db_name = other_shard.try(:name) unless id == Rails.env
  temp_db_name = Shard.default.name if id == Rails.env

  case config[:adapter]
    when 'postgresql'
      temp_db_name ||= 'public'
      create_statement = lambda { "CREATE SCHEMA #{db_name}" }
      password = " PASSWORD #{::ActiveRecord::Base.connection.quote(config[:password])}" if config[:password]
    when 'sqlite3'
      if db_name
        # Try to create a db on-disk even if the only shards for sqlite are in-memory
        temp_db_name = nil if temp_db_name == ':memory:'
        # Put it in the db directory if there are no other sqlite shards
        temp_db_name ||= 'db/dummy'
        temp_db_name = File.join(File.dirname(temp_db_name), "#{db_name}.sqlite3")
        # If they really asked for :memory:, give them :memory:
        temp_db_name = db_name if db_name == ':memory:'
        db_name = temp_db_name
      end
    else
      temp_db_name ||= self.config[:database] % self.config
      create_statement = lambda { "CREATE DATABASE #{db_name}" }
  end
  sharding_config = Switchman.config
  config_create_statement = sharding_config[config[:adapter]].try(:[], :create_statement)
  config_create_statement ||= sharding_config[:create_statement]
  if config_create_statement
    create_commands = Array(config_create_statement).dup
    create_statement = lambda {
      create_commands.map { |statement| statement.gsub('%{db_name}', db_name).gsub('%{password}', password || '') }
    }
  end

  shard = Shard.create!(:name => temp_db_name,
                        :database_server => self) do |shard|
    shard.id = options[:id] if options[:id]
  end
  begin
    if db_name.nil?
      base_db_name = self.config[:database] % self.config
      base_db_name = $1 if base_db_name =~ /(?:.*\/)(.+)_shard_\d+(?:\.sqlite3)?$/
      base_db_name = nil if base_db_name == ':memory:'
      base_db_name << '_' if base_db_name
      db_name = "#{base_db_name}shard_#{shard.id}"
      if config[:adapter] == 'sqlite3'
        # Try to create a db on-disk even if the only shards for sqlite are in-memory
        temp_db_name = nil if temp_db_name == ':memory:'
        # Put it in the db directory if there are no other sqlite shards
        temp_db_name ||= 'db/dummy'
        db_name = File.join(File.dirname(temp_db_name), "#{db_name}.sqlite3")
        shard.name = db_name
      end
    end
    shard.activate(Shard.categories) do
      ::Shackles.activate(:deploy) do
        begin
          if create_statement
            Array(create_statement.call).each do |stmt|
              ::ActiveRecord::Base.connection.execute(stmt)
            end
            # have to disconnect and reconnect to the correct db
            if self.shareable? && other_shard
              other_shard.activate { ::ActiveRecord::Base.connection }
            else
              ::ActiveRecord::Base.connection_pool.current_pool.disconnect!
            end
          end
          shard.name = db_name
          old_proc = ::ActiveRecord::Base.connection.raw_connection.set_notice_processor {} if config[:adapter] == 'postgresql'
          old_verbose = ::ActiveRecord::Migration.verbose
          ::ActiveRecord::Migration.verbose = false
          ::ActiveRecord::Migrator.migrate(Rails.root + "db/migrate/") unless create_schema == false
        ensure
          ::ActiveRecord::Migration.verbose = old_verbose
          ::ActiveRecord::Base.connection.raw_connection.set_notice_processor(&old_proc) if old_proc
        end
      end
    end
    shard.save!
    shard
  rescue
    shard.destroy
    raise
  end
end

#destroy ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 49

def destroy
  raise "database servers should be set up in database.yml" unless Rails.env.test?
  self.class.send(:database_servers).delete(self.id) if self.id
end

#fake? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/switchman/database_server.rb', line 54

def fake?
  @fake
end

#shard_name(shard) ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 181

def shard_name(shard)
  if config[:shard_name]
    config[:shard_name]
  elsif config[:adapter] == 'postgresql'
    if shard == :bootstrap
      # rescue nil because the database may not exist yet; if it doesn't,
      # it will shortly, and this will be re-invoked
      ::ActiveRecord::Base.connection.schemas.first rescue nil
    else
      shard.activate { ::ActiveRecord::Base.connection_pool.default_schema }
    end
  else
    config[:database]
  end
end

#shards ⇒ Object 



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# File 'lib/switchman/database_server.rb', line 70

def shards
  if self.id == Rails.env
    Shard.where("database_server_id IS NULL OR database_server_id=?", self.id)
  else
    Shard.where(:database_server_id => self.id)
  end
end

#shareable? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/switchman/database_server.rb', line 58

def shareable?
  @shareable_environment_key ||= []
  environment = ::Shackles.environment
  explicit_user = ::Shackles.global_config[:username]
  return @shareable if @shareable_environment_key == [environment, explicit_user]
  @shareable_environment_key = [environment, explicit_user]
  username = self.config[:username]
  username = self.config[environment][:username] if environment && self.config[environment] && self.config[environment][:username]
  username = explicit_user if explicit_user
  @shareable = self.config[:adapter] != 'sqlite3' && username !~ /%?\{[a-zA-Z0-9_]+\}/
end